1. Field of the Invention
The invention concerns a feed apparatus comprising a conveyor belt, the conveyor belt comprising modules with an upper and a lower surface, the modules having hinge eyes pivotally hinged to each other perpendicular to a feed direction, and at least one rotatable and toothed driving wheel meshed with the conveyor belt.
2. Description of the Prior Art
EP 0 380 203 discloses a feed apparatus comprising a toothed wheel and a belt, and where the toothed wheel drives the belt forward by means of recesses which grip into a transverse rib on the undermost surface of the belt. The sprocket wheel thus exerts a force on the diagonal surface of which the side of the middle rib is formed, so that as soon as there is a strain on the belt an upward-pressing of the belt up over the tooth will take place. The risk that the belt hops totally off the toothed wheel is significantly great. There is thus a relatively poor engagement between belt and sprocket wheel.
Besides, there is no lateral guiding of the belt, which is sufficiently expedient in that a rib placed between the teeth serves as a lateral guide, so that the belt does not become displaced sideways, but the function of the rib itself causes meat remains and the like to become embedded between the teeth. The only possible method of cleaning the belt is through use of a high pressure cleaner, which is very difficult.
Finally, the belt lays flat when running back, thus not enabling fluid to be automatically drained, since the lower surface of the belt is totally flat.
The present invention provides a feed apparatus which is not encumbered with the disadvantages of the known system, and where it is possible to achieve an optimum force transmission to the belt itself, which will occur by the teeth of the sprocket wheel achieving origin of force at the hinge eyes, thus enabling the force transmission to materialize close to the center line of the axis of the hinge eyes, in the same way enabling a favorable lateral steering of the belt, so that the risk that the belt hops off the toothed wheel is minimized.
This object is achieved with a feed apparatus where the pressure receiving surface of the teeth wholly or partially has contact against at least the outer surface of its own hinge.
The feed apparatus works by the toothed wheels gripping inward in the outer surface of the modules, in that the teeth are formed in such a manner which enables their pressure receiving surface, that is the surface which under rotation of the toothed wheel presses against the belt, to press against the surface of the hinge eyes, and thus a force transmission takes place directly to the belt. The belt can withstand considerable stresses, all the way up to 2500 Newtons, whereas the known belt systems only allow stress influences of 1200-1300 Newtons.
Since the teeth are engaged against the hinge eyes, the pressure on the belt will in all cases remain approximately unchanged, so that the belt will not hop off, since there is not a force-arm relationship which would otherwise be in effect in the case of known systems.
By providing a feed apparatus according to the invention, there is sufficient room for the teeth of the toothed wheel between the hinge eyes, and since there is room for the teeth between the hinges because of the diagonal surfaces, a favorable pressure surface for the sprocket wheel is achieved, which simultaneously sideway-steers the belt.
The pressure receiving surface against the hinge eyes is practically perpendicular, so that there is no pressure on the belt in the perpendicular direction, but only forward. Therefore, it is avoided that the belt passes over the teeth upon application of stress, so that the belt hops off.
An optimization of the interaction between the toothed wheel and hinge eyes is achieved, so that the force transmission from the toothed wheel occurs close to the center line of the axis of the hinge eyes.
Room for a rib on the undermost surface of the belt is achieved, the rib extending along the center line of the module and parallel with the lengthwise sides which facilitates drainage of liquid from a lower surface of the modules and further strengthens the belt.
An optimum sideways-steering is achieved, using a loose fit of the toothed wheel in the space between the hinge eyes, though not large enough so that a twisting of the toothed wheel or the belt will be displaced from a position between the two hinge eyes.